The exhaust on my bike was in bad need of refinishing so I decided to modify it before blasting and powder coating it. I have always wanted a little more volume without it being obnoxious, and wanted to turn the exhaust away from the rear wheel. I cut the back end of the muffler off along with a five inch or so section on the left side to gain access to the reversion tubes. I cut the tubes out and am in the process of welding the case back on. I am having a little trouble with burn through on the thin gauge casing, so I tacked the rest of it together and put it on the bike to hear it roar. Wow is it booming and loud now! This will certainly quiet down significantly once it is all closed up, but the hooligan in me just couldn't resist!

Don't be surprised if you lose power. The stock exhaust is very good with a broader power band than most aftermarket exhaust systems and any changes in the exhaust will certainly require ECU remapping.

But you could be changing the tuned length and flow characteristics which could alter the fueling needs.

On the other hand, I've always wondered how much of an impact the Helmholtz chamber at the collector had on the tuned length with regards to pulse reflection. Sort of like a termination box - does anything after it factor into tuned length or not.

"Glad you put that qualifier in there. There's a few out there that absolutely make more power everywhere over stock."

None of them, including yours, will make more power on their own. An engine is a power system that is a series of optimizations and trade offs. There are no free lunches. At the very minimum, fuel maps should be altered as well. Any design change on one end must be balanced with changes elsewhere. It is a total misconception that free horsepower exists by just changing an exhaust pipe.

Well I had to see how loud it is going to be in its fully welded state so I utilized metal duct tape to close up all the seems. It actually has a nice sound to it, louder but by no means obnoxious. Then for even more fun I pulled it back off and ran it with open pipes. It was borderline painful! I didn't rev it past 3k and the noise was actually a little less obnoxious above idle, but I am pretty sure the neighbors were happy when I shut it off.

There was a post a while back where the owner drilled thru the S baffle from the outlet, no cutting/welding, to get some volume from the stock muffler. I would guess this has less of an impact on performance, and may provide a "louder" pipe. I have an extra muffler and may give this a try before I buy an ECM and put on the Saron.

This was done in another post with very poor outcome. The best way to do it is open up the back chamber, cut out the two perforated tubes, weld back up then cut the two turnouts off and weld on your favorite style turn out. Put in an Ebr race ecu designed for HMF and enjoy.

Couple pictures and videos in there. I had a fabricator friend practice his pie cut welds on the TIG... probably made it better than MIG process working with the thin gauge the exhaust is stamped out of.

All that said, it sounds deeper a tad louder, but the quality is not so great. It's too "blatty" and metallic sounding. Can't wait to get a Barkers or Keda pipe back on there to make the sound more "round" and pleasant.

Well I spent some time on it this past weekend. I ran out of .035 flux core so purchased .030 to avoid putting as much heat in. I made some good head way but still chasing undercuts and holes. I put it back on the bike to get a seat of the pants feel. It is still quieter than I prefer and I didn't notice any changes in the way it runs.

Well like too many of my projects I got off to a good start and then ran into the reality of being a husband and father of three kids...never enough time for unnecessary projects. But I have run it all summer welded up with a few small holes in the can. The exhaust sound level has increased slightly since I put it back on, but from my point of view it just keeps getting better. I have lots of ideas of where I want to go from here, and hopefully this winter I can find the time to finish. I have not noticed any appreciable difference in power and/or drive-ability, she is still easy to ride anywhere and an absolute blast at WOT!!!

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